Optical system and camera device having same

An optical system, comprising:

• a first lens group comprising, sequentially from an object side to an image side, at least one lens and having a negative refractive power, a second lens group comprising at least one lens and having a positive refractive power, and a third lens group comprising at least one lens and having a negative refractive power,
• wherein during focusing, distances between the first lens group and an imaging plane and between the third lens group and the imaging plane on an optical axis are fixed, and the second lens group moves along the optical axis,
• wherein when a lateral magnification of the second lens group focusing at infinity is b2, a lateral magnification of the third lens group focusing at infinity is b3, a focal length of the optical system focusing at infinity is f, a focal length of the second lens group is f2, a focal length of the third lens group is f3, a total value of distances from a lens face closest to the object side to a lens face closest to the image side in each lens group is OAL123, and a maximum image height is Y,
• at least one of the following formulas (1) to (4) is satisfied:
• -
• 1.2
• ≤
• f
• ⁢
• 3
• /
• f
• ≤
• -
• 0.1
• (
• 1
• )
• -
• 0.4
• ≤
• b
• ⁢
• 2
• ≤
• -
• 0.06
• (
• 2
• )
• 0.3
• ≤
• O
• ⁢
• A
• ⁢
• L
• ⁢
• 123
• /
• Y
• ≤
• 2.3
• and
• 1.
• ≤
• b
• ⁢
• 3
• ≤
• 1.3
• (
• 3
• )
• 0.6
• ≤
• f
• ⁢
• 2
• /
• f
• ≤
• 0.9
• ,
• and
• (
• 4
• )
• wherein the second lens group is movable in a direction orthogonal to the optical axis, and it is satisfied that:
• 1.
• ≤
• (
• 1
• -
• b
• ⁢
• 2
• )
• ×
• b
• ⁢
• 3
• ≤
• 1.9
• .